Bepotastine, (+)-(S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino]butyric acid, is a non-sedating, highly selective antagonist of the histamine H1 receptor. It has a stabilizing effect on mast cells, and it suppresses the migration of eosinophils into inflamed tissues. It has three mechanisms of action: mast cell stabilizer, histamine antagonist, and modulator/inhibitor of eosinophils. Bepotastine and pharmacologically acceptable salts thereof have an antihistaminic action and an antiallergic action. They are also characterized in that secondary effects such as stimulation or suppression of the central nerve often seen in the case of conventional antihistaminic agents can be minimized, and can be used as effective pharmaceutical agents for the treatment of human and animals (PCT Patent Publication No. WO98/29409).
Bepotastine besilate has been approved in Japan for systemic use in the treatment of allergic rhinitis since 2000 and urticaria/pruritus since 2002. It is marketed in Japan by Mitsubishi Tanabe Pharma Corporation (formerly Tanabe Seiyaku Co., Ltd.) under the brand name TALION®. ISTA Pharmaceuticals' eye drop formulation of bepotastine besilate, BEPREVE® (bepotastine besilate ophthalmic solution) 1.5% w/v, was approved by the U.S. Food and Drug Administration (FDA) in September 2009 for the treatment of ocular itching associated with allergic conjunctivitis.